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Biomedical subjects

I Lanzl

Publications and source records attributed to I Lanzl.

7 recordsLinked to original sources
PubMed2005

[Comparison of diameter response of retinal arteries and veins to flickering light. A clinical study with healthy people].

PURPOSE: The aim of this study was to compare the diameter response of retinal arteries and veins after provocation with flickering light regarding the amplitude and temporal course. METHODS: The study included 26 healthy volunteers. The vessel diameter was automatically and continuously measured by the retinal vessel analyzer. The examination consisted of a baseline measurement (100 s) followed by five periods of 20-s flicker light provocation and 80-s follow-up observation. RESULTS: A diameter dilation was observed immediately after the end of the flicker period in arteries (6.9+/-2.8%) and veins (6.5+/-2.8%, difference n.s.). The quotient of arterial and venous dilation (AVDQ) was 1.25+/-0.69 (range: 0.2-2.8). A significant correlation of age and arterial or venous dilation or the AVDQ was not observed. The arterial diameter reduced faster than the venous and reached a minimum of -2.7+/-1.4% at 25.9+/-10.8 s after the end of the flicker phase. The veins were dilated by 0.5+/-1.3% at the time of the maximal individual arterial constriction (p<0.0001). CONCLUSIONS: Flicker-evoked response of retinal arteries and veins did not differ in the dilative amplitude but in the temporal course of the abatement of the dilation.

Adult↗
PubMed2002

Functional analysis of retinal vessel diameter reaction to artificially raised intraocular pressure in glaucoma patients with and without dorzolamide therapy.

BACKGROUND: Examination of the influence of dorzolamide on the autoregulation of retinal vessel diameter in glaucoma patients. PATIENTS AND METHODS: Eleven patients with primary open angle glaucoma (age 60 +/- 11) without medication and four weeks after starting therapy with dorzolamid eye drops three times daily were examined in the study. Short-time rise of intraocular pressure (IOP) was obtained via suction-cup. Functional reaction of the diameter of a segment of a retinal artery and corresponding vein were assessed by retinal vessel analyzer. RESULTS: Dorzolamid lowered the IOP from 23.3 +/- 1.3 to 17.6 +/- 2.2 mmHg (p = 0.004). Therapy did not influence the absolute diameter of retinal vessels regarding maximal dilatation caused by the pressure rising provocation. In eyes with treatment the diameter decreased faster to baseline values (arteries 100 sec, veins 220 sec) compared to those without treatment (arteries 350 sec, veins 480 sec). CONCLUSION: Dorzolamid might possibly be able to accelerate autoregulation of retinal vessels in response to short term artificial IOP increase.

Adult↗
PubMed2002

Retinal Vessel Analysis--new possibilities.

Retinal Vessel Analysis is a new technique to assess behavior of large retinal vessels based on diameter measurements. The Retinal Vessel Analyzer (RVA) measures continuously on-line obtaining data in relation to time and local position. Possible analysis tools include (a) Time Course Analysis of physiological, pathological, or therapy induced changes; (b) Local Course Analysis to recognize local narrow or wide vessel segments along the vessel; (c) Vasomotoric Analysis to determine vasomotions and blood pressure related diameter changes; (d) Functional Analysis to examine dynamic behavior e.g. the ability to autoregulate and (e) Functional Imaging to visualize functional parameters of vessels in single vessel segments. RVA is thus able to recognize and study different autoregulation mechanisms.

Fluorescein Angiography↗
PubMed2000

[The radiological diagnosis of an intraorbital bullet projectile].

Beside conventional X-ray examination, ultrasound and computer tomographic examination are accepted radiologic techniques to assess the extend of damage of intraorbital injuries. With the exception of a few reports in the literature there is agreement that intraorbital metallic foreign bodies and gun-shot bullets represent a contraindication for magnetic resonance (MR) imaging examination because of artificial imaging side effects and the potential of secondary dislocation of the metallic foreign body due to ferromagnetism. By means of the case reported here it is shown that this general opinion is not universally valid. Depending on the elemental metallic composition of foreign bodies and gun-shot bullets it is demonstrated that MR examination allows high-resolution illustration and in some cases is advantageous compared with other radiologic imaging techniques.

Adult↗
PubMedDate not supplied

Imaging of eye movement with fast MRI.

PURPOSE: Imaging of eye movement disorders has so far been restricted to the semifunctional cine mode of CT and MRI. Since real-time imaging of eye movement is necessary to investigate dynamic disorders, the aim of our study was to implement a fast MR technique to investigate eye movement in a real-time mode. METHOD: Six healthy volunteers and three patients suffering from end-point nystagmus were examined with fast MR sequences while performing the following eye movements: holding different gaze positions, reading a defined text to demonstrate saccadic movements, and holding a primary gaze position and maximal end-point position to cause nystagmus when present. RESULTS: In all cases, we were able to delineate eye movement with fast MRI. Anatomic and functional information could be obtained simultaneously for the first time through observation of saccadic and pursuit eye movements. CONCLUSION: Fast MRI allows for the assessment of dynamic eye movement without the restrictions of cine mode and is able to provide the clinician with additional information in the evaluation of functional movement disorders.

Adult↗
PubMedDate not supplied

Blood pressure effects on retinal vessel diameter and flicker response: a 1.5-year follow-up.

PURPOSE: The study examined the influence of individual blood pressure changes overtime on retinal vessel diameter and the latter's response to flicker light. METHODS: The diameter of a retinal arterial and venous segment was measured continuously on-line with a Dynamic Vessel Analyzer in 20 patients twice (mean interval between examinations of 24 months). Eleven patients had no cardiovascular disease. Nine patients had arterial hypertension and were untreated at the time of the first measurement; at the time of the second measurement they were undergoing various antihypertensive therapies. Each test consisted of a 50-s baseline plus three 20-s periods of flicker stimulation followed by an 80-s period of observation. During the examinations the blood pressure was measured at 1-minute intervals. RESULTS: In the hypertension group changes in the mean arterial blood pressure (MAP) correlated significantly with changes in the arterial baseline diameter (y = -0.1 - 0.37x, r =0.74, p (increase) <0.03). A comparison of the two measurements showed no such relationship in the group of cardiovascularly healthy subjects. The venous baseline and the arterial and venous flicker response did not change significantly in either group between the two measurements and showed no relationship to blood pressure changes. CONCLUSIONS: In hypertensive subjects, long-term therapy-related changes in blood pressure induced a change in the arterial baseline by approximately +3.7 microm/-10 mmHg MAP. An influence of lowering MAP to the arterial flicker response could not be detected.

Antihypertensive Agents↗